Heated roll deposit cleaning apparatus

ABSTRACT

Steam is jetted against the circumferential path of contact of yarn on a roll heated to above 100*C. This greatly reduces buildup of yarn spin-finish and &#39;&#39;&#39;&#39;monomer&#39;&#39;&#39;&#39; on the hot roll, thus reducing the frequency at which the process must be interrupted for cleaning the roll.

[ 1 June 18, 11974 [56] References Cited UNITED STATES PATENTS 2,129,2749/1938 Hartmann et al. 611/205 E X 2,533,103 12/1950 Givens et al.(18/205 E X Primary Examiner-Harvey C. Hornsby Assistant Examiner-PhilipR. Coe

[57] ABSTRACT Steam is jetted against the circumferential path ofcontact of yarn on a roll heated to above 100C This greatly reducesbuildup of yarn spin-finish and monomet" on the hot roll, thus reducingthe frequency. at which the process must be interrupted for cleaning theroll.

4 Claims, 1 Drawing Figure APPARATUS Inventor: Albert H. Bruner,Pensacola. Fla.

Assignee: Monsanto Qornpany, St. Louis, Mo.

Sept. 15, 1972 Appl. No: 289,409

Related US. Application Data Continuation-impart of Ser No 88,592, Nov.1970, abandoned.

68/205 E, 118/70 1nt.11)06c 1/08, D06c 7/02 Field of Search.......l.....118/70; 68/205 E, 5 E, 68/5 D; 8/1493, 151.2

Unite States Patent [19] Burner HEATED ROLL DEPOSIT CLEANING [22] Filed:

1 HEATED ROLL DEPOSIT CLEANING APPARATUS This application is acontinuation-in-part of copending application Ser. No. 88,592, filedNov. 12, 1970, and now abandoned.

The invention relates to reducing buildup of deposits on a heated rollcontacting a yarn.

A number of processes involve treatment of a moving yarn with heat forvarious reasons. Virtually all yarns are coated with a liquidspin-finish composition prior to the heat treatment in order tolubricate the filaments, reduce static, etc. The liquid finishcompositions are typically aqueous emulsions of oils, dispersants,emulsitiers, and the like. When such a coated yarn contacts a rollheated to above 100C, a deposit builds up on the roll in thecircumferential path or track of the yarn on the roll. The depositchanges the coefficient of fric tion between the yarn and roll, and tosome extent reduces the heat transfer from the roll to the yarn. Thisdeposit includes partially degraded components of the finishcomposition. The deposit may also include various partially degradedoligomers (commonly referred to as monomers") related to the polymerfrom which the yarn is formed, such as nylon, polyester, acrylics, etc.

According to the present invention, the rate of buildup of thisundesirable deposit is substantially reduced by jetting a fluid hotterthan 100C. against the path or track of the yarn on the roll, thusreducing the frequency at which the process must beint'errupted to cleanthe roll.

One principal object of the invention is to provide apparatus forreducing the rate of buildup of the undesirable deposit on a rotatingheated roll.

A further object is to provide apparatus of the above character whereinthe rate of buildup is reduced by jetting a fluid stream at atemperature greater than 100C. against the path of yarn contact on theroll.

Other objects will in part appear hereinafter and will in part beobvious from the following description in conjunction with theaccompanying drawing, wherein the single FIGURE is a perspective view,partially schematic and partially broken away, of the preferredembodiment of the invention.

The FIGURE shows the invention as used in the drawing of a continuousfilament yarn such as nylon 66. As illustrated in this context, yam isfed from schematically illustrated yarn supply 22 to pass in severalwraps about feed roll 24 and its associated separator roll 26. Yarn 20has on its surface a conventional spinfinish of the usual oils,antistatic agents, emulsifiers, etc. Supply 22 can be a conventionalpackage of spun yarn, or can be a spinning position, in. which case thespin-finish is applied. by finish roll 23 shortly after the filamentssolidify. Feed roll 24 is driven at a given surface velocity by motor28. Yarn 20 next passes through a slot in insulated chamber and in aplurality of wraps about draw roll 32 and its associated separator roll34. Draw roll 32 is driven at a surface velocity higher than that offeed roll 24 by motor 36, to draw the yarn. Yarn 20 next passes out ofchamber 30 and is wound or otherwise collected by yarn takeup' device38.

Roll 32 is heated to above 100C, for example by internal heatersenergized through electrical leads 40. Tube 42 extends axially parallelto the axisof roll 32, and is positioned between roll 32 and separatorroll 34.

Tube 42 extends through the right or rear wall of chamber 30, and ismounted for reciprocation parallel to the axis of roll 32. Slowlyrotating cam 44 in cooperation with spring 46 reciprocates tube 42 at arate of a few cycles (e.g., 5) per minute. A source 48 supplies theheated fluid (preferably steam) under pressure through flexible tube 50to the interior'of tube 42.

As yarn 20 passes around rolls 32 and 34, it contacts roll 32 in aseries of circumferential paths or tracks. Since yarn 20 takes only apartial wrap about roll 32 during each pass, only a portion of eachtrack is contacted by yarn 20 at any given time, but all portions ofeach track are repetitively brought into and out of contact with therunning yarn 20 as roll 32 rotates. Some of the finish and sometimessome monomefi are deposited on these tracks and tend to be degraded bythe heat. According to the invention, jet nozzles or orifices 52 arealigned with and direct streams of heated high velocity fluid onto theportions of the yarn tracks which are not in contact with the yarn atthat time, vaporizing or otherwise blasting off most of the depositsbefore they have time to degrade and adhere to roll 32. The streamimpinge against roll 32, as opposed to merely being tangent thereto.Nozzles 52 are positioned near but not touching roll 32. For example,the clearance may be about one-eighth to one-fourth inch. In operation apoint on the track on the roll surface repetitively and alternatelycontacts the yarn and is then impinged against by the gaseous stream.

The heated fluid is preferably continuously discharged against roll 32,particularly if the fluid temperature is different from the'temperatureof roll 32. This aids in maintaining a constant temperature of roll 32by avoiding variable thermal loading on the roll.

Use of the invention does not totally eliminate deposits with commonlyused finish compositions. However it materially reduces the rate atwhich deposits build up. This results in two distinct advantages, thefirst of which is that the heated roll can be run longer betweenauxiliary cleanings, thus resulting in less machine down time" andgreater productivity. The second advantage is that the roll has a longerservice life before the surface must be refinished. The auxiliarycleaning process gradually changes the surface finish characteristics,and hence the surface frictional properties of the roll. By reducing thenumber of times that the roll must be subjected to auxiliary cleaning ina given period of time, the expensive surface refinishing of the roll isrequired less often.

Of the various heated fluids tested, steam has been found to be thebest, and saturated steam is particularly effective. Hot air isconsiderably less effective, although it does usually provide to somedegree the objects and advantages of the invention.

In the preferred embodiment when treating nylon 66 yarn, orifices 52have diameters of 0.020 inch and have a length of 0.065 inch. Saturatedsteam is supplied by supply 48 at 260C. and p.s.i.g. to tube 42. Roll 32is heated to 200C. by the internal electrical heaters, and has adiameter of 6 inches. Rolls 24 and 32 may be operated at speeds to drawyarn 20 at normal draw ratios, and at speeds up to 5,000 yards perminute. Although the invention is illustrated in the context of usingtheheated roll as a positively driven draw roll, the invention is notlimited to this particular use. The heated roll can be an idler roll(driven by the yarn), and

can be used for relaxing, setting, or otherwise heattreating the yarn.

In order to minimize steam consumption and to insure high velocity inthe steam impinging on roll 32, the steam orifices are preferably quitesmall. To clean an area at least as wide as the tracks made on roll 32by yarn 20 with a narrow jet stream, steam tube 42 and orifices 52 arereciprocated with a component of motion parallel to the axis of roll 32by cam 44, as noted above. The axial motion of tube 42 required issmall, with about one-fourth to one-half inch being normally sufficient.The steam pressure is not particularly critical, although bettercleaning is generally obtained at higher pressures and temperatures.Preferably steam at at least V; sonic velocity is used. The temperatureof the gaseous stream is generally not critical, and may be between100C. and 1,000C. or even higher. Advantageously the gas temperature maybe the same as the roll temperature. However, this is not essentialsince the amount of gas required for cleaning is generally less athigher temperatures than at lower ones, and accordingly the amount ofheat added to the roll by the gaseous stream or streams will ordinarilynot materially affeet the temperature of the roll. That is to say,ordinarily the heat added to the roll by the hot gas will not besufficient to maintain the roll at the desired temperature, and thatseparate means will normally be required for heating the roll.

Chamber 30 is provided with an exhaust line 54 for removing the steam.This largely prevents steam from escaping through the slots by whichyarn 20 enters and leaves chamber 30, and subsequently condensing onnearby equipment.

By the term thermally stable yarn is meant a yarn which is not melted ordegraded to an undesirable degree by contact with the heated roll. Theamount of heat transferred to the yarn during each pass of the yarnacross the roll is, for a given roll temperature, a function of thecontact time between the yarn and the roll. Ordinarily the rolltemperature will be lower than the critical yarn temperature at whichthe yarn melts or degrades, but it may be higher (up to 500C.) if thecontact time is correspondingly reduced. Selection of an appropriateroll temperature and contact time for a given yarn is within the scopeof one skilled in the art.

I claim:

1. Yarn treating apparatus, comprising a. a rotating roll;

b. means for heating said roll to a temperature above 0. means forsupplying yarn to be treated to said roll whereby said yarn contactssaid roll in at least one track extending circumferentially around saidroll, said yarn containing on its surface a liquid finish;

d. jet means for impinging on said at least one track a fluid heated toabove 100C, said jet means being reciprocated in a path having acomponent of motion parallel to the axis of said roll; and

e. means for collecting said yarn from said roll.

2. The apparatus defined in claim 1, wherein said fluid is steam.

3. The apparatus defined in claim 1, wherein said jet means continuouslyjets steam against said at least one track.

4. The apparatus defined in claim 1, wherein said roll and said jetmeans are mounted within an insulated en-

1. Yarn treating apparatus, comprising a. a rotating roll; b. means forheating said roll to a temperature above 100*C.; c. means for supplyingyarn to be treated to said roll whereby said yarn contacts said roll inat least one track extending circumferentially around said roll, saidyarn containing on its surface a liquid finish; d. jet means forimpinging on said at least one track a fluid heated to above 100*C.,said jet means being reciprocated in a path having a component of motionparallel to the axis of said roll; and e. means for collecting said yarnfrom said roll.
 2. The apparatus defined in claim 1, wherein said fluidis steam.
 3. The apparatus defined in claim 1, wherein said jet meanscontinuously jets steam against said at least one track.
 4. Theapparatus defined in claim 1, wherein said roll and said jet means aremounted within an insulated enclosure.